1. Field of the Invention
The present invention relates to a structure of an antenna for a mobile phone, and more particularly, to a structure of an antenna for a mobile phone capable of reducing hazardous electromagnetic waves transmitted to the user's head and body.
2. Description of the Related Art
Hereinafter, a “mobile phone” refers to, unless specified otherwise, various potable communicating equipments, which comprise the mobile phone and hand-set of wire phone used for mobile communications such as IMT2000, CDMA, PCS, TDMA, GSM, AMPS and the like.
A “front-side” of the mobile phone refers to, unless specified otherwise, the side of the mobile phone on which a speaker and a microphone are disposed which becomes in contact with user's face (i.e., check) during communication.
Electromagnetic wave refers to the wave propagating at the light speed in a space where two physical components of the electric field and the magnetic field resonate each other, and also it is generated from various electric/electronic appliances. It has been confirmed that the heat generated by the electromagnetic wave with high frequency arriving at the body to raise the temperature of human body, and the Stimulus to the nerve system by the electric current induced by low frequency electromagnetic wave adversely affect the health of human body.
As the communication technologies advance, the mobile phone is used close to the user's head for extended time, and it has widely penetrated into the life of ordinary people. Since the electromagnetic wave emitted from the mobile phone is absorbed into the body, the effects caused by the electromagnetic wave of the mobile phone to the human body have been studied in various aspects.
Because of public opinion concerning the hazards caused by the electromagnetic wave of the mobile phone, it is difficult to use the mobile phone in hospitals, oil-stations and the like where delicate electronic equipments are used. Also, there have been intense discussions on whether the electromagnetic wave generated by a mobile phone affects the healthy of body or not.
Since an apparatus for converting the transmitted radio wave signals into voice signals in the mobile phone typically is integrated in the inside of the receiver, it is reported that hot spots affecting the body are generated in the receiver during communication, and thus generate substantial amount of hazardous electromagnetic wave. Also, since the conventional antenna of the mobile phone is installed at the outside of the mobile phone, and it has non-directional radiation pattern to sense the electromagnetic waves in all directions a large amount of electromagnetic wave is absorbed in the body, particularly in the head.
In order to protect the body from the hazards of electromagnetic wave, a number of developed countries have regulated the MPE (Maximum Permissible Exposure) to the human body. Thus, in Korea, study meetings on this topic have been organized, by private citizens, and a standard for protecting the body from the electromagnetic wave generated by the mobile phone and the like has been prepared. In USA, a standard for protecting the body from electromagnetic wave was prepared, and from 1999, the SAR of mobile phones with respect to the user's head portion (1.6 mW/g) is controlled tightly.
Therefore, the mobile phones satisfying the international regulations concerning the SAR become more important, and an antenna, which is able to meet the regulations, is needed.
Although it has been proposed to use a pad on the surface of the hearing part of the mobile phone to absorb the electromagnetic wave, it adversely affects the appearance of the mobile phone, and its effects are insufficient as well.
On the other hand, the present invention provides an antenna structure installed inside of a housing of a mobile phone and increasing the gain of antenna by arranging an electromagnetic wave absorber between the circuit board and the antenna.
This structure of the antenna, however, must overcome the limitation of the space to be installed within the housing since the size of the mobile phone becomes more compact.